Field of the Invention
The present invention relates to a vehicle equipped with an electronic stability control (ESC) system and an electronic shift lever (shift by wire, SBW), and more particularly, to a P-range engagement method of a vehicle and a control device thereof, which is capable of achieving the function of an electronic parking brake (EPB) in a vehicle that is not equipped with an EPB.
Description of Related Art
Recently, vehicles equipped with an ESC system and an EPB in order to secure passengers' safety have been increasingly developed and released in the market.
The ESC system functions to control the orientation of the vehicle body on behalf of a driver in an emergency. While the representative active safety device for vehicles in the 20th century was an anti-lock brake system (ABS), the representative safety device for vehicles in the 21st century may be an ESC system.
An ABS functions to prevent wheels from locking, and a traction control system (TCS) functions to sense wheel spin and to decrease the output of an engine in response thereto. The aforementioned ESC system performs the combined function of the ABS and the TCS, as well as other additional functions.
Respective sensors of the ESC system continually monitor the orientation of the vehicle and the driver's steering operation, that is, a steering angle. If the direction in which the vehicle is traveling becomes misaligned from the steering angle, the ESC system regards this as a dangerous situation, and immediately supplies individual braking force to the respective wheels, thereby controlling the orientation of the vehicle. In other words, the ESC system is an active safety device for vehicles, which rectifies a driver's mistake.
The ESC system stabilizes the movement of the vehicle body when the vehicle deviates from the traveling course by applying individual braking force to the four respective wheels. The ESC system includes a hydraulic modulator, a control device, and a variety of sensors. The sensors detect a steering angle and a wheel speed and transmit the detected information to the control device, and the hydraulic modulator increases the braking pressure in respective brakes. The ESC system not only applies braking force to the respective wheels, but also decreases the output of an engine.
An EPB is a parking brake system that is controlled in an electronic manner, which differs from a conventional wire-type system. While the vehicle is stopping, a computer checks a vehicle speed, an engine rpm, and whether the brake is in an operational or non-operational state, and the parking brake is locked depending on the degree to which the driver steps on the brake pedal.
Therefore, even when the driver takes his or her foot off the brake pedal in the stopped state, there is little possibility of the locking state of the parking brake being released. If the driver steps on an accelerator pedal, the locking state of the parking brake is automatically released, and accordingly the driver can move the vehicle. Further, the EPB has advantages of preventing the vehicle from moving downward when the driver starts to drive on an uphill road from the stopped state and of preventing the driver from needing to frequently step on the accelerator pedal when driving in a congested area. While traveling, since the computer determines that the vehicle is moving by detecting the vehicle speed, the EPB is never operated.
However, if the electronic stability control system, the electronic parking brake and the electronic shift lever are all mounted together to the vehicle, the structure becomes complicated and the manufacturing cost is increased.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.